Editing Photolithography (section)

== Experimental methods ==
{{See also|Next-generation lithography|Nanolithography}}
Photolithography has been defeating predictions of its demise for many years. For instance, by the early 1980s, many in the semiconductor industry had come to believe that features smaller than 1 micron could not be printed optically. Modern techniques using excimer laser lithography already print features with dimensions a fraction of the wavelength of light used – an amazing optical feat. New techniques such as [[immersion lithography]], dual-tone resist and [[multiple patterning]] continue to improve the resolution of 193&nbsp;nm lithography. Meanwhile, current research is exploring alternatives to conventional UV, such as [[electron beam lithography]], [[X-ray lithography]], [[extreme ultraviolet lithography]] and [[ion projection lithography]]. Extreme ultraviolet lithography has entered mass production use, as of 2018 by Samsung<ref>{{cite web | url=https://m.pulsenews.co.kr/view.php?year=2018&no=650219 | title=Samsung Elec becomes world's 1st to use EUV at 7nm process - Pulse by Maeil Business News Korea }}</ref> and other manufacturers have followed suit.

Massively parallel electron beam lithography has been explored as an alternative to photolithography, and was tested by TSMC, but it did not succeed and the technology from the main developer of the technique, MAPPER, was purchased by ASML, although electron beam lithography was at one point used in chip production by IBM.<ref>{{cite web | url=https://www.chiphistory.org/725-maskless-lithography-circa-1977 | title=Maskless Lithography: A recurring dream }}</ref><ref>{{cite journal | url=https://ui.adsabs.harvard.edu/abs/2010SPIE.7823E..16P/abstract | bibcode=2010SPIE.7823E..16P | title=Direct write electron beam lithography: A historical overview | last1=Pfeiffer | first1=Hans C. | editor-first1=M. Warren | editor-first2=Wilhelm | editor-last1=Montgomery | editor-last2=Maurer | journal=Photomask Technology 2010 | date=2010 | volume=7823 | doi=10.1117/12.868477 | s2cid=108646584 }}</ref> Electron beam lithography is only used in niche applications such as photomask production.<ref>{{cite web | url=https://ieeexplore.ieee.org/document/5760021 | title=MAPPER: High Throughput Maskless Lithography | date=January 2009 | pages=1–5 }}</ref><ref>{{Cite web |last=Weiland |first=Marco |title=MAPPER: High throughput Maskless Lithography |url=https://www.cea.fr/cea-tech/leti/english/Documents/Spie-Litho/03%20-%20ML2%20-%20MAPPER%20-%20M%20Wieland%20-%20LETI%20WS%20SPIE%202018.pdf |website=cea.fr}}</ref><ref>{{cite web | url=https://semiengineering.com/manufacturing-bits-feb-5/ | title=Manufacturing Bits: Feb. 5 | date=5 February 2019 }}</ref><ref>{{cite web | url=https://www.eetimes.com/leti-receives-mapper-300-mm-e-beam-lithography-platform/ | title=Leti receives Mapper 300-mm e-beam lithography platform | date=21 July 2009 }}</ref><ref>{{cite web | url=https://www.design-reuse.com/news/19290/multiple-electron-beam-maskless-lithography-platform.html | title=MAPPER and TSMC Take Next Step in Exploring Multiple E-beam Lithography for IC Manufacturing at 22 nanometer node and Beyond }}</ref>